Canon i450 Woes!

I've used my trusty Canon i450 to print photos for many years and have been hesitant to move from it since I find the quality adequate and the ink tanks affordable (especially compared to the multi-cartridge photo printers; the i450 uses a single cartridge).

One dozen pieces of photo paper and countless amounts of ink later, I think I finally got around to solving the problem, but I want to throw this one out to see if anyone has some insight or a possible fix.

I had wanted to print a photo for a 2.5" x 3.5" frame. Unfortunately, the photo was a bit too narrow, as I had cropped part of it, so I imported the photo into Pages and created a grey box behind it. When I printed the photo on 4" x 6" paper, it did not print as a rectangle as it should have. Instead, the shape more closely resembled a parallelogram.

The printer was last used a few weeks ago for a few color documents, so I knew it was OK. (Both cartridges were fresh, too, as I had replaced them after not having used the printer in about two years). I tried it again, thinking it was a fluke, and noticed the same problem.

Wanting to rule out a printer problem, I tried another photo I had wanted to print from iPhoto. This one came out fine.

I decided to go to an alternate solution for the first photo. I pasted the photo and background into Preview, creating a new document. Again, the problem persisted. I tried switching the orientation of the paper. This solved the problem but created another one–the photo could not center itself on the page no matter how many settings I adjusted.

To recap what I had observed so far: the print worked fine in iPhoto when fed in portrait mode in the printer and when I tried landscape mode in Preview (which resulted in a clipped photo). Landscape mode in Preview or Pages resulted in a faulty print.

I decided to try the Preview file, exported as a JPEG, in iPhoto. However, iPhoto only feeds paper in portrait mode. While this worked fine for the 4" x 6" I had printed earlier, it didn't cooperate for this photo again!

Finally, I decided to trick Pages. I set up a blank document in portrait mode, figuring it would be plenty large enough if I fed the paper in using landscape mode. This wound up working!!

My question: what is up with my printer and how can I prevent this from happening? It seems the smaller photo on larger paper is the issue, but only when the page is fed portrait-wise. If I feed the paper landscape-wise, there is no issue.

I've had this printer for nine years and have never experienced this sort of problem. I do realize it's old for a printer and ancient for a consumer inkjet, but this is unlike any printer problem I've experienced (I've been using inkjets since the original StyleWriter and have never seen anything this strange). Any insight would be greatly appreciated!